You have to remember that when you learn the limit of your car you will know what to expect. For me the Mini stock bars made the car feel loose and unpredictable....a recipe for disaster if your driving in a spirited fashion. With the stiffer sway bar I can judge so much better where the limit is on any type of road or condition.

For example...this is a little winded sorry.
We have an undeveloped sub division with only the streets paved...no homes. The streets are freashly paved and flat. There is a hughe circle there that we play around in..we made a little road course there. Its about 150' in diameter and a near perfect circle.

Before the sway bar..
When we would go around this circle we experienced oversteer and understeer....thats OK but it was almost always a surprise. NOT perdictable and it always made me uncomfortable.

After the sway bar.....
We went to the same route we always go...and when I hit the circle I was damn near close to flat out and hanging on..passenger was hanging on for dear life...LOL. We ran so hard that we threw the car into limp mode because the YAW control threw a code and threw a check engine light that I was able to clear with my OBDII reader.

SO thats my assesment of the sway bar. I am 100% happy with this mod and I am no way connected to Alta just happy with the mod.

 

now put on some good tires and really be amazed =)

 

Red Bull, do you think 19mm would make a diff in the JCW? I'm not sure which size I want to get, since I mostly do street driving. I suppose I could get a 22mm and put it on softest setting to start, but I don't want to get more swaybar than I need.....Thoughts???

 

22mm is alot of swar bar, especially comin from the stock 17mm, cuz a sway bars stiffness grows exponentially when you increase the diameter....a 20mm might be perfect for you then...not the as much as the 22mm, but more noticeable than the 19mm

 

I've been pondering a related issue, based around there being a big gap between the stiffness of a 19mm and 22mm rear sway bar.

Seems to me that the first setting of a 19mm bar is so little change vs. OEM as to be useless. It takes a 30-50% change in sway bar stiffness on the MINI to make a difference that's worth changing.

On the other hand, with a 22mm bar, I can tell you from experience that the hardest setting is suitable only for extreme track use, and the two lower ones are still quite a bit if you have other things that decrease understeer, which I do.

You can find a nice chart of calculated swaybar stiffness at http://www.whiteline.com.au/docs/bulletins/010barup.pdf

These numbers are calculated, but this is a case where the physics are pretty simple and the calculations are straightforward. These ratios will apply when the effective "arm" length of the bars compared is the same, and this should be true of any steel bar with three positions - the middle hole should be at the stock length in order to keep the connecting link at nearly the same angle.

So to recap, here are the relevant ratios for solid swaybars, in the range that applies to MINIs. 9.9x would mean 9.9 times stiffer than a 17mm "S" bar:

Cooper 16mm .79x
S 17mm 0.0
19mm 1.56x
20mm 1.92x
22mm 2.80x

The placement of the holes also affects the stiffness. Given that the center hole of a 3-holer has to be in the original position, and that all the mfrs. of three-holers drill the three holes equally spaced, you can figure that the harder position creates about 1.4x times the center position, and the softer hole will be about .75 of the middle hole, i.e. you will get a choice of ratios, again, related to the stock S 17mm bar:

Cooper 16mm .79x
S 17mm 0.0
19mm 1.17x - 1.56x - 2.18x
20mm 1.44x - 1.92x - 2.69x
22mm 2.10x - 2.80x - 3.92x

These ratios all work out to within a few % of the figures specified by the manufacturers, which is close enough for decision-making. Here's my observations:

- Softest position on a 19mm bar would be useful on a Cooper, but not a useful change on an S.
- The softest position on a 22mm bar is more than 2x stiffer than stock, and that is quite a bit for many street-only cars and drivers.
- 19 mm bar doesn't go firm enough, and a 22mm bar doesn't go soft enough.
- It would be useful to have an only a little-more-stiff position available, for use in winter, for example. Somewhere around 1.5x would be nice.
- Looks like a 20mm bar is the sweet-spot diameter for a MINI that's not a track-monster...

For myself, before recently adding IE Fixed camber plates, I was happy with the 22mm on Medium. After the camber plates, and with other mods that decrease understeer, I've been using the 22mm bar on soft. That's still a bit tail-heavy for me now, so I've ordered a 20mm bar, which will give me a very slightly softer Middle setting for normal spirited use, while still offering a useful range of adjustment both harder and softer.

The 20mm bar is seldom seen here in the US, but one is available from MiniMania or JSCspeed. The bar is the same, from Whiteline in Australia.

 

Old Rick this is a very good analogy. Before I ordered a rear swaybar I thought long and hard on which size to order. I also took into account that in the future my suspension may change and wanted to have the adjustability so that I would not be replacing parts that I have already purchased. By adding I.E. fixed plates I needed a little less stiffness and when adding the Madness lower front strut brace I found that I needed to add a little stiffness back in. I purchased the Web Extreem or Tarrett bar and have no regrets. This bar gives me infinite adjustability and I can dial in whatever stiffness that suits the combination of suspension parts now or in the future if I decide to go to coilovers. The original cost of this bar is right up there but the quality of materials, design, ease of installation, and added endlinks has proven to me to be a good choice.
Steve

 

I might be wrong, but I thought the stock swaybar on my 09 JCW was 18.5mm. I'm wondering if a 19mm will even make a difference. It may make more sense to go with the 22mm and put it on it's softest setting since I do mostly street driving.

Don't know which way to go, since on one hand I read all these posts saying 19mm is the way to go and 22mm is too much, then other threads saying the opposite It looks like you and Red Bull are quite happy with the 22mm for daily driving....

 

Hello
The stock JCW sway bar that came out of my car is 17.5MM. I measured it myself.

 

 

Don't you mean "... will put you in the modified call"? The stock class does not allow modified rear sway bar.

 

I think that is the size that comes with the Dealer/Self installed JCW suspension. ...Factory JCW comes with stock suspension.

 

that's pretty crazy; had never heard of that occurring. I guess I don't go looking for people's posting about tracking their car, but have still read a good many. had never heard of that happening.

p.s. I bet you must have lifted the inside rear wheel off the road for a good stretch.

 

Spoke to the mechanic at Mini, your not far off. He said I raised a rear wheel and the G meter built into the car for all the traction devices must have read that the car turned over.....putting it in limp mode. If I turned the DTS off I would not have had this happen...I thought I had it turned off but guess I didn't.

 

Very good to know. Thanx. I'd read folks stating the lifting of the inside tire as a "down side" of going real stiff in the rear, but I'd never known what that could affect beyond losing that tire's grip to assist in traction (however slight that grip may be as the inside wheel's very unloaded with say a 19mm rear bar). Thanx again.

 

OldRick, great post, thanks for the info. I have the Alta 19mm on the softest setting and the improvement I noticed was almost, uh....nothing. Time to move to the middle setting. I will likely end up on the stiffest, even after camber plates, but for now it will be one step at a time.

BTW, I have one of those TSW X-brace's on its way to me. Would this have any noticeable effect on understeer? I realize it is not designed to directly address understeer, but I am thinking it would tend to make the car understeer less?

 

mini_racer
I can not speak for the TSW X brace personally but I think the outcome would be similar to my experience with the Madness lower brace. After installation It actually added understeer and I had to increase the stiffness of my Tarrett/Web rear bar to bring the handling back to neutral. I think if you do a search you will find others with the OMP lower brace to have had the same experience.
Steve

 

OK, thanks and I am planning to go to the next (i.e middle) stiffness hole on my 19mm already, so after all done I might need to go all the way.

It is good to have an adjustable bar.

 

Hopefully you will not run out of adjustment on your 19MM bar. This is one of the main reasons I went with the Tarrett/Webb bar.
Steve

 

The Tarrett is a good looking bar...If I had seen that one before I bought the 22mm bar I think I would have went with that one. Love all the setting you can play with. I just purchased the Alta adjustable links...so that should give me more adjustment.

 

Red Bull
I'm confused with your statement on Alta adjustable links giving you more adjustment. The only adjustment that I'm aware of for the endlinks is to remove any preload from side to side on the bar along with giving you additional strength.
Steve

 

I got the 20mm bar installed today, replacing a 22mm solid Mini-Madness bar.

The 22mm was set on softest after I had IE Fixed camber plates installed in front couple of months ago. The car was showing considerable oversteer anytime I'd feed a little gas coming out of a turn - it really wanted to pull inside with even a little bit on the gas.

M-M specs the 22mm solid bar at 2.25x the OEM bar.

I set the new 20mm Whiteline bar at its middle position - theoretically 1.92x OEM.

The car became much better balanced, at least with all-season tires on - I can now go from mild understeer to mild oversteer by getting on the gas after the apex.

Yup - I'm pleased to confirm that suspension design theory really works!

 

You can adjust the length on the Alta end links...I will post a picture soon.

 

Red Bull
I am aware that the length is adjustable and really it's designed to eliminate any preload side to side along with giving you added strength. This would be a must have to corner balance your car. But it really does not increase/decrease the effective rate of the bar setting.
Steve

 

I understand that but, you can increase the length and change the position...just like changing the setting on the bar by changing the location on the 3 holes where the end link attaches.

 

Changing the length of the end-links does not affect the stiffness of the bar or its effect on handling in any way. It's not like changing the setting on the bar at all.

The end-link adjustment just there to remove any side-to-side pre-load when you are corner-balancing the car with coilovers. A waste of money if you don't.